The inventor of the subject variety, Rene Nicolai, was the owner of Rene Nicolai Nursery, which propagated and sold Malling Nine (M9) apple tree root stock. Root stock are propagated by placing plants in a stool bed which encourages root growth and then dividing the resulting roots into individual plants. Over the years Mr. Nicolai searched the M9 stool beds for M9 mutants which were superior to the parent variety in those characteristics which are desirable for apple tree root stock.
The subject clone was selected in 1967 from a large stool bed of M9 plants that was planted in 1960 at the Rene Nicolai Nursery at Linderstoot, 22-B-3820 Alken, Belgium. The original source of the plants in the bed was the East Malling Research Station in England. Following its selection, the clone was assigned a number (RN19) and was propagated for further testing and evaluation.
Since all original M9 root stocks have been found to be virus infected, the RN19 plants were subsequently heat treated by application of dry heat, in order to obtain virus-free testing, the new root stock cone was again exposed to multiplication techniques (stooling) followed by continued testing and evaluation.
Virus-free RN19 progeny plants were expanded into small stool bed plantings at several locations which were planted separately in order to examine the new variety's individual characteristics in small semi-commercial stool bed sites. Since 1974 nearly 40,000 plants of the subject variety have been planted at the following six sites and, in the process, may generations of the tree have been produced.
1. A site at Deveaux, Belgium was planted in the spring of 1974 with 1,500 plants of the subject clone.
2. A site at Bordeaux, France was planted in 1977 with 200 plants of the subject clone.
3. A site at Wissenhoeve, Belgium was planted in the spring of 1980 with 2,058 plants of the subject clone.
4. A site near St. Truiden, Belgium was planted in the spring of 1982 with 100 plants of the subject clone. 5. A site at Henkaenrts, Belgium was planted in the spring of 1986 with 3,250 plants of the subject clone.
6. A site at Ephrata, Wash. was planted in the spring of 1990 with 2,000 plants of the subject clone.
Clone RN19 was subsequently finally selected as a rootstock clone that continues to possess growth and rooting characteristics that are distinctly different from its M9 parent.
It distinguished itself in these beds from its M9 parent in the following ways:
1. The subject clone produces many more lateral limbs (feathers or spurs) than its M9 parent and grows more robustly in the stoolbed (FIGS. 1 and 2; Charts 1 and 2). The average increase in height of daughter plants growing in the stoolbed is approximately 20% (FIG. 6, M 9; and FIG. 7, RN19) and the average increase in the number of feathers produced is approximately three-fold at Bordeaux, France and almost six-fold at Ephrata, Wash. (Charts 1 and 2). A significant difference in the average length of the individual feathers produced is also noted (Chart 2). Because of RN19's more robust growth and its characteristic habit of producing more and larger feathers, an increased difference in the average number of leaves produced per daughter plant also occurs (Chart 2). A slight increases difference in the average number of nodes per shoot and in the average stem circumference is also noted (Chart 2). RN19 exhibits a much lesser early bloom characteristic than does its M 9 parent (Chart 3). Leaf size (adding the length and width together) and the length of the leaf particles are consistently smaller than the virus-free M 9 (Chart 4).
CHART 1 ______________________________________ Percent of Layer Plants with Side Limbs (Feathers) (Test Stooling Beds at Bordeaux, France) Rootstock Year Clone 79/80 80/81 81/82 82/83 Average ______________________________________ M9 13 8 25 0 11.4 (virus-free) RN8 8 6 13 0 6.8 RN19 41 32 44 19 34.0 RN29 39 22 35 15 27.8 ______________________________________
CHART 2 ______________________________________ Growth Characteristics (Test Stooling Beds at Ephrata, Washington) Length Number Number Length Number Circum- of of of of of ference Rootstock Shoot Nodes/ Spurs/ Spur Leaves/ of Stem Clone (cm) Shoot Shoot (cm) Shoots (cm) ______________________________________ M9 66.80* 39.20 3.00 1.50 53.00 3.24 RN8 62.10 42.10 1.80 1.20 57.20 3.80 RN19 78.20 41.00 18.60 8.60 88.30 3.51 RN29 86.20 45.60 21.40 10.30 100.00 3.54 ______________________________________ *All numbers shown are the average of 100 plants selected at random.
CHART 3 ______________________________________ Bloom Characteristics (Research Station at Gorsum, Belgium - 1985) Rootstock % of Rootstocks With Bloom Clone (1 Year From Stoolbed) ______________________________________ RN8 29 RN19 4 RN29 0 M9 15 (virus-free) ______________________________________
CHART 4 ______________________________________ Leaf Size and Respetive Petiole Length of Respective Rootstock (Test Stooling Beds at Bordeaux, France) Rootstock Length, L Width, W L + W Length of Clone (mm) (mm) (mm) Petiole ______________________________________ M9 101.7 63.8 165.5 32.5 (virus-free) RN8 98.8 73.6 172.4 34.0 RN19 91.4 60.0 151.4 30.8 RN29 85.5 57.1 142.6 28.5 ______________________________________
2. The subject clone has the ability to produce many more rooted daughter plants per mother plant and per meter of stoolbed row than its M 9 parent (FIGS. 4 and 5; Charts 5, 6 and 7). Data collected at the Bordeaux test site in France shows an approximately three-fold increase in the number of daughter plants produced over a four-year period and data collected at the Deveaux test site in Belgium shows an approximately two-fold increase over six- and nine-year periods.
CHART 5 ______________________________________ RN19 Stoolbed Production (Deveaux, Belgium) No. Mother Plants - 555 Length of Bed (m) - 185 ______________________________________ Year 82/83 83/84 84/85 85/86 86/87 ______________________________________ Grade (mm) 10/12 1,000 825 575 2,250 4,000 8/10 0 0 1,500 0 0 6/10 17,200 12,800 0 0 0 6/8 0 0 12,490 11,300 9,650 5/7 0 0 0 0 0 4/6 8,800 8,100 10,080 10,300 12,700 04 0 1,600 0 0 150 #2s 4,000 2,9400 2,700 2,000 5,300 Totals 31,000 26,225 27,345 25,850 31,800 Per Mother Plant 20.67 17.48 18.23 17.23 21.20 Per Meter 62.00 52.45 54.69 51.70 63.60 ______________________________________ Average Year 87/88 88/89 89/90 90/91 82/91 ______________________________________ Grade (mm) 10/12 1,250 525 0 1,075 8/10 4,225 4,500 3,900 5,150 6/10 0 0 0 0 6/8 9,950 8,000 9,050 3.100 5/7 0 0 0 10,100 4/6 9,500 6,700 10,500 2,600 04 0 0 0 0 #2s 5,700 3,000 10,500 2,600 Totals 30,625 22,725 33,850 27,825 Per Mother Plant 20.42 15.15 22.57 18.55 19.06 Per Meter 61.25 45.45 67.70 55.65 57.17 ______________________________________
CHART 6 ______________________________________ M9 (Virus-Free) Stoolbed Production (Deveaux, Belgium) No. Mother Plants - 561 Length of Bed (m) - 187 ______________________________________ Year 82/83 83/84 84/85 85/86 86/87 ______________________________________ Grade (mm) 10/12 225 100 250 750 464 8/10 0 0 450 0 0 6/10 4,150 2,950 0 2,350 2,200 6/8 0 0 3,400 0 0 5/7 0 0 0 0 0 4/6 1,800 1,600 2,200 1,600 3,000 04 0 300 0 0 0 #2s 700 800 500 500 1,400 Totals 6,875 5,750 6,800 5,200 7,064 Per Mother Plant 12.25 10.25 12.12 9.27 12.59 Per Meter 36.76 30.75 36.36 27.81 37.78 ______________________________________ Average Year 87/88 88/89 89/90 90/91 82/91 ______________________________________ Grade (mm) 10/12 75 -- -- -- 8/10 450 -- -- -- 6/10 0 -- -- -- 6/8 2,700 -- -- -- 5/7 0 -- -- -- 4/6 2,200 -- -- -- 04 0 -- -- -- #2s 400 -- -- -- Totals 5,825 -- -- -- Per Mother Plant 10.38 -- -- -- 11.14 Per Meter 31.15 -- -- -- 33.43 ______________________________________
CHART 7 ______________________________________ Average Number of Plants Per Stoolbed Mother Plant (Test Stooling Beds at Bordeaux, France) Year Planted and Age Rootstock 79/80 80/81 81/82 82/83 Clone 2-Yr 3-Yr 4-Yr 5-Yr Average ______________________________________ M9 1.2 2.6 .5 4.0 8.3 (virus-free) RN8 2.1 3.9 3.8 6.4 16.2 RN19 2.6 4.4 6.5 9.1 22.6 RN29 4.4 5.6 5.7 11.3 27.0 ______________________________________
3. Leaves of the subject clone are more acutely tipped and have sinuate serrations along their sides than leaves produced on its M 9 parent (FIG. 3). The average number of leaf serrations per centimeter of length was consistently less than those recorded on leaves of its M 9 parent (Chart 8).
CHART 8 ______________________________________ Leaf Characteristics (Test Stooling Beds at Ephrata, Washington) Number of Leaf Rootstock Serrations Clone per cm ______________________________________ M9 3.5** RN19 2.7 ______________________________________ *All numbers shown are the average of 200 leaves taken from 100 plants selected at random.